38 DISCOVERY REPORTS 



91. Trochammina nana (Brady) (F no) (SG 136) (A 193). 

 Three stations: 312, 313, 417. 



Frequent at St. 313 ; rare at St. 417; a single specimen at St. 312. 

 Pearcey: 337A "rare". 



92. Trochammina soldanii, sp.n. (Plate I, figs. 32-34). 

 Three stations: 226, 290, 303. 



Test free, rotaloid, inequilateral ; spire depressed but visible on the dorsal side which 

 is slightly umbilicate, the ventral side, exhibiting only the last convolution, being very 

 deeply umbilicate. Consisting of about four convolutions, each of seven chambers. The 

 two earlier convolutions are constructed of chitin and fine cement and the chambering 

 is very distinct ; the two later convolutions are increasingly coarse in structure and it is 

 difficult to distinguish the chambers; the last convolution often contains large sand 

 grains out of proportion to the rest of the test. Peripheral edge rounded ; aperture very 

 small on ventral side, near the junction of the final chamber with the preceding con- 

 volution. 



Width up to 1-3 mm. Thickness at the final chamber 0-9 mm. Very rare, only an 

 occasional specimen at each station. The species is very distinctive, isomorphous to 

 some extent with Rotalia soldanii, d'Orbigny. Its nearest relative is probably T. rossensis, 

 Warthin (W. 1934, FRS, p. 3, text-figs. 1-3), from the Bay of Whales, Ross Sea, 280 fms., 

 from which it diff^ers in its larger size, more deeply depressed ventral umbilicus and 

 greater number of chambers. 



93. Trochammina bradyi, Robertson (Fin) (SG 137) (A 196). 

 Three stations: 312, 417, 438. 



A single large typical specimen at each station. Its rarity as compared with the 

 Discovery records is remarkable. None of the malformed variety referred to in A 196 

 was observed. 



94. Trochammina globigeriniformis (Parker and Jones) (F iioa) (SG 140) (A 197). 

 Five stations: 301, 313, 406, 417, 428. 



Not uncommon at Sts. 313 and 417 ; very rare elsewhere. All the specimens are small. 

 Pearcey: 313, 337A, 342, 417, 447 "nowhere common". 



95. Trochammina inconspicua, Earland (SG 139) (A 199). 

 Eight stations: 226, 300, 312, 313, 338, 406, 417, 428. 



Not infrequent at Sts. 300 and 417 ; very rare elsewhere. 



Pearcey's records of T. globigeriniformis may perhaps include specimens of this allied 

 species. 



Genus Ammosphaeroidina, Cushman, 1910 



96. Ammosphaeroidina sphaeroidiniformis (Brady) (SG 142) (A 206). 

 Two stations: 313, 428. 



A large specimen at St. 313, and two smaller at St. 428. 



